Carbon is widely used as a fuel, an electrode, a fiber, an absorbent, and an additive. Carbon is most produced from petroleum or coal. However, petroleum and coal are so-called fossil fuels, and depletion thereof is a matter of deep concern.
On the other hand, cellulose (C6H10O5)n, which is contained in wood or grass, is the most abundant hydrocarbon on the earth. Since cellulose is a hydrocarbon, carbon (C) is obtained by excluding a water (H2O) component therefrom.
Thus, as disclosed in Japanese Patent Application Laid-Open Publication No. 2008-201651 (JP-A 2008-201651), studies have been conducted on the production of carbon using cellulose as a starting material.
The apparatus for manufacturing porous carbon as disclosed in JP-A 2008-201651 includes a drying furnace, a carbonizing furnace, a high temperature water vapor generating apparatus, and a deodorizing furnace. Wood chips as a raw material are dried in the drying furnace, and are subsequently subjected to a high temperature treatment in the carbonizing furnace. The resulting product is discharged from the carbonizing furnace in the form of activated carbon.
At this time, superheated vapor at 750° C. to 950° C. is generated in the high temperature water vapor generating apparatus which uses LPG (liquefied propane gas) as a heat source, this superheated vapor is supplied to the carbonizing furnace, and thus the high temperature treatment is performed. The high temperature vapor that has been used in the carbonizing furnace is supplied to the drying furnace, and is provided for drying. The air generated during this drying is accompanied by foul odor. Thus, the air obtained after the drying is deodorized through incineration in the deodorizing furnace. Kerosene is used for this incineration.
As such, in order to generate superheated vapor at 750° C. to 950° C., a large amount of liquefied propane gas is consumed, and a large amount of kerosene is consumed for deodorization and incineration. That is, the technology disclosed in JP-A No. 2008-201651 requires large amounts of fossil fuels.
Hence, under the current situation in which there is a concern for depletion of fossil fuels, there is a demand for a production technology for obtaining carbon using less heat energy.